| Summary: | 碩士 === 逢甲大學 === 化學工程學所 === 97 === A novel amperometric sensor for hydrogen determination based on PtxPdy/Nafion and PtxRuy/Nafion electrodeshave been developed in this study. The binary PtxPdy and PtxRuy alloys were deposited on Nafion by Takenaka-Torikai(T-T) method. The characteristics and the sensing performances of the PtxPdy and PtxRuy/Nafion electrodes were investigated.
The results showed that the response current was influenced by gas flow rate significantly. The optimum response current was obtained at gas flow rate of 100 sccm. For PtxPdy/Nafion electrodes, as the applied potential is 0.6 V (vs. Ag/AgCl (NaCl 3 M)), the current is controlled by mass transfer. A linear relationship between response current and hydrogen concentration was observed in the detection range from 100 to 1000 ppm. Among all the electrodes, the Pt22Pd78/Nafion electrode was shown the best sensitivity of 17.7 nA/cm2ppm. The response time for all the PtxPdy/Nafion electrodes were in the range from 24 to 37 ± 2 s. The Pt22Pd78/Nafion electrode possessed shortest response and recovery time. Both NO (1000 ppm) and CO (2000 ppm) were tested as the potential interfering species, it found that the Pt22Pd78/Nafion electrode exhibited better selectivity toward hydrogen than NO and CO.
The binary PtxRuy/Nafion electrodes all showed the better sensitivity toward hydrogen compared to the Ru/Nafion electrode at 0.6 V (vs. Ag/AgCl (NaCl 3 M)), and their sensitivities increasd in the order of Ru < Pt46Ru54 < Pt48Ru52 < Pt71Ru29 < Pt80Ru20 < Pt. The response time of the PtxRuy/Nafion electrodes toward hydrogen has been found to in the range form 38 to 45 ± 2 s. the interference test showed that as the content of Ru increased, it could substantially reduce the interference of a mixed gas containing 500 ppm H2 and 1000 ppm CO.
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